In many episodes, alien art work and wall hangings were in reality discarded protective Styrofoam shipping box liners from tape recorders used by fellow Desilu/Paramount show Mission: Impossible (1966), spray painted various colors and arranged into various combined forms.
You'd make a splendid computer, Mr Spock. Spock
Spock: That is very kind of you, Captain!
In most hand-to-hand combat scenes throughout the series, with the exception of close-up shots, the characters fighting are played by very obvious stunt doubles and not the principal actors.
In a few occasions in the latter part of the first season, the credit, in all-uppercase, for "SCRIPT SUPERVISOR", has the first word misspelled "SCPIPT".
The second pilot of the series, "Where No Man Has Gone Before" was originally cut a bit differently than the version that exists on VHS and DVD. In the original cut, there is an opening narration by Captain Kirk stating: "Enterprise Log: Captain James Kirk commanding. We are leaving that vast cloud of stars and planets which we call our galaxy. Behind us: Earth, Mars, Venus, even our sun are specks of dust. A question: what is out there in the black void beyond? Until now our mission has been that of space law regulation, contact with Earth colonies and investigation of alien life. But now, a new task; a probe out into where no man has gone before." followed by the words "STAR TREK" appearing on screen. They fade away and are replaced by "STARRING WILLIAM SHATNER." The episode then moves into act one, with the words "STAR TREK ACT I" appearing on screen. The episode then proceeds as normal until Scotty says "It's begun transmitting, sir." at which point, the words "TONIGHT'S EPISODE 'WHERE NO MAN HAS GONE BEFORE'" appear. After which, there is an extended pan of the Enterprise hallways with the titles "CO-STARRING LENOARD NIMOY AS MR. SPOCK" appearing and fading away, followed by "GUEST STARS GARY LOCKWOOD AND SALLY KELLERMAN." Over this scene, the red alert klaxon blares and Lieutenant Kelso repeatedly saying "Bridge to all decks. Condition: alert!" We also see Gary Mitchell walking around the corridors as well until finally cutting to Kirk and Spock entering the turbolift, at which point the episode continues as normal. Additionally, the end credits were much different in this original cut. Instead of the normal "Star Trek" theme playing, a different piece is used and the credits only credit the supporting characters; none of whom are referenced by name. (For example: PAUL FIX AS: SHIP'S DOCTOR, GEORGE TAKEI AS: CHIEF PHYSICIST, JAMES DOOHAN AS: ENGINEERING CHIEF, etc.)